Playing around with the File API

file.html

<input type="file" id="input">
<br />
<pre id="output"></pre>

<script>
  var output = document.getElementById("output");
  var input = document.getElementById("input");

  function handleFiles() {
    var file = this.files[0];
    var reader = new FileReader();
    reader.addEventListener("loadend", function() {
      output.innerHTML = reader.result;
    }, false);

    reader.readAsText(file);
  }

  input.addEventListener("change", handleFiles, false);

</script>